National nutrition surveillance.

National Nutrition Surveillance includes nutritional assessment surveys to ascertain the extent of malnutrition in populations, to identify possible causes, to establish baseline data for monitoring nutrition, and to select mechanisms for nutrition surveillance (in a restricted sense). An example of the results from a recent nutritional assessment survey in the United States is the negative association of obesity with energy intake, exercise and socioeconomic status, which has implications for public nutritional policy. Nutritional monitoring measures changes in population nutrition over time. An example of the results from nutritional monitoring is the unexpected and presently unexplained decrease in serum cholesterol levels of middle-aged women in the United States over the past decade. Nutritional surveillance in the restricted sense not only identifies malnutrition but is administratively organized to intervene rapidly. National Nutrition Surveillance depends on metabolic and clinical research to decide on its priorities. This research indicates that malnutrition involves more than under-nutrition, and greater emphasis should be given in National Nutrition Surveillance to this wider context of malnutrition. These results will in turn help set priorities for basic and applied research in nutrition. It is important that the research community participate in the review presently under way of the role of the National Center for Health Statistics in National Nutrition Surveillance.